Bee Health News
Nosema Ceranae Found in UK
Found on the web site of CSL. It was issued from the NBU in November 2007:
Three hundred and nine samples have now been tested for the presence of Nosema apis and Nosema ceranae using real-time PCR (Polymerase Chain Reaction, a technique used in molecular biology to replicate apiece of DNA. Ed). All positive results were confirmed using published assays for the detection of these pathogens. Positive results have therefore been confirmed using 2 methods both based on the detection of species specific DNA. Of these samples 31 samples testing positive for N.apis (10%), 14 for N.Ceranae (4.5%) and 3 (1%) testing positive for both Nosema species. N.Ceranae positives were confirmed across seven counties of England (Cornwall, Essex, Lincolnshire, Hertfordshire, Hereford and Worcestershire, Greater London, North Yorkshire) and three in Wales (Glamorgan, Powys, Dyfed).
N,Ceranae infections have been reported not to show typical signs of Nosema infection. Therefore we recommend beekeepers check their colonies for adult bee diseases. Treatment using the usual veterinary medicine treatment is effective against Nosema infections in honeybee colonies. It is also important to treat effectively against Varroa mite infestations.
We will carry out a more detailed survey to estimate the prevalence and impact of both Nosema species across England and Wales. Samples of DNA extracts from the European foul brood study, imported bees and historical samples stored in the NBU labs will be rescreened.
No-one can yet know how this might affect our bees.
Information on Nosema ceranae can be found on the internet.
Colony Collapse Disorder (One Members View)
Time had been allotted at the recent Apimondia Congress for a round table discussion on this topic which is causing so much concern, especially in the USA. The session began with a review of the situation where a number of eminent beekeeping experts gave their thoughts and explanations about the problem. It was stated that pollinators have been in decline for the past fifty years and have halved from the numbers in the 1940s. It was mentioned, for instance, that the almond crop in America needs 1.2 million colonies at the beginning of each year for pollination. The opinion was that not all losses were due to CCD. Normal annual losses were about 17%; last year it was 30%, therefore suggesting that an estimated 13% were due to CCD. The media would have us believe that it is the cause of most losses but there were a lot of misconceptions. Bee samples from around America taken at one point in time were being analysed to try to determine any specific cause. Protozoa found within the last ten years in the USA is the Asian Nosema ceranae, associated in Spain and Portugal with heavy losses. A newer virus has been found called Israeli Acute Paralysis Virus (IAPV). Israel has provided samples because of unexplained losses not associated with Varroa or other factors. IAPV has been found in weak or unhealthy bees and may be an indicator of poor bee health. How widespread is IAPV in America? It has also been found in Australian bees.
Losses in the past have been explainable but the recent losses are more extreme. Even so there is a need to avoid misinformation to the press. Main reasons given for losses are:
new pesticides e.g. imaprochloride; conventional pesticides; beekeepers mixing the two; accumulation of anti-varroa treatments; damage by viruses (there are 14 known plus IAPV plus how many unknown?); decrease of biodiversity; new diseases e.g. nosema ceranae; stress due to migration: bee feed notably corn syrup (is it free from pesticides?); Hertzian problem - phone masts, radar, GPS: global warming; DIY treatments; GM crops.
With regard to the last mentioned the conclusion is that the data available not provide evidence of harm to bees. Bt crops have more insect life than untreated ones and the pattern of CCD does not correlate with GMO crop sites. The aim of a pathogen is to infiltrate, breed and evolve/mutate. Beekeepers help by having high density of hives and replacing bees as one hive die out. A “fast” growing virus does not kill - the bee dies and the pathogen has no time to reproduce. A ’slow’ virus has more time to inflict more damage.
A working group with 66 members has been set up to find ways of preventing bee losses, exchange information, co-ordinate monitoring and identify factors for the losses.
(The above is a summary of the notes I made at the session. I could not record everything but this may help to give an overview of the situation)
Gillian Searle
Devon & Cornwall Foulbrood Inspections 2007
Information & map courtesy of Beebase
Exotic Pest
Small Hive Beetle (SHB), Aethina tumida
Native to sub saharan Africa (although it is reported in Egypt), and until recently was thought to be restricted to that region. It is a minor pest of weak honeybee colonies and stored honey supers in its native range. However, the SHB was confirmed for the first time outside Africa in Florida, USA, in May 1998, and since then has become widespread across the USA (in more than 30 US states). The SHB was detected in New South Wales and Queensland in Australia in October 2002.
It can survive the colder climates of the United States and has been reported as far north as Minnesota in the US and Manitoba, Canada (traced to imports of unrefined wax from Texas, USA), therefore it is certain that the beetle would survive under UK conditions. Of more concern is the fact that in October 2004 SHB larvae were identified in an unauthorised consignment of queen bees imported into Portugal (again from Texas, USA) demonstrating the potential for transport in this commodity also. It is important we all do everything possible to detect the beetle as early as possible if it arrives in the UK. Early detection would allow the possibility of control action to be targeted promptly, preventing the SHB from becoming widespread.
The NBU, in liaison with Defra and the Welsh Assembly Government, is developing contingency plans and surveillance measures to equip it with the tools to tackle the threat of an SHB outbreak in England and Wales. Since 2003, ABIs have been increasing the statutory surveillance programmes to specifically monitor for the beetle and tropilaelaps mites (see below). The NBU has been using its beekeeper and apiary database (‘Beebase’) and Geographical Information Systems (GIS) to help prioritise this programme and target ‘At Risk Apiaries’ (ARAs). For example, apiaries within close proximity to high-risk areas such as ports, freight terminals or fruit and vegetable importers are targeted and regularly inspected. Using the GIS systems, ARAs are given mathematical risk scores and inspections can be prioritised readily. More detailed information may be found in the leaflet The Small Hive Beetle – A serious new threat to European apiculture.
Should Aethina tumida be discovered in England or Wales, emergency measures will be implemented. The essential aspects of these are communication, assessment of the extent of infestation, eradication and containment or control. The approach taken for control in an attempt to slow down spread would depend highly upon the extent of the infestation; if restricted, an eradication method could be used. Otherwise, a containment scheme will implemented through the use of 'Statutory Infected Areas'. Further details will become available once the contingency plans have been finalised. Similar arrangements should apply in Scotland and Northern Ireland.
Tropilaelaps spp.
Tropilaelaps clareae and T. koenigerum are serious mite parasites of honeybees. The primary host of the parasitic brood mite T. clareae Delfinado & Baker (Laelapidae: Acari) is the large Asian honey bee Apis dorsata, but the parasite is also associated with A. laboriosa, A. mellifera, A. cerana and A. florea. It is thought to be restricted to tropical or sub-tropical regions but its exact geographical range is unknown. The furthest west it has been found is in Khorasan and Sistan va Baluchestan provinces in Iran close to the Pakistan and Afghanistan borders, and the furthest east is Papua New Guinea.
The females of T. clareae are light-reddish brown and about 1.0 mm long x 0.6 mm wide, and the males are almost as large as the females. The life cycle and parasitism of A. mellifera is similar to that of Varroa destructor. T. clareae readily infests colonies of A. mellifera in Asia, particularly where colonies produce brood continuously. Adult female mites enter cells containing larvae where reproduction takes place within sealed brood cells. The mother mite lays three to four eggs on mature bee larvae 48 hours after cell capping. Development requires approximately 6 days, and the adults (including the mother mite) emerge with the hatching adult bee then search for new hosts. Mites move rapidly across the brood combs and are therefore easier to spot than varroa, although they are much smaller. T. clareae has a shorter reproductive cycle than V. destructor, so when both mites are present in the same colony, T. clareae populations build up more rapidly.
T. koenigerum was first reported in 1982 as a new species of parasite on A. dorsata in Sri Lanka. It has also been found on A. laboriosa, A. cerana and A. mellifera in Kashmir. It has a similar life cycle to T. clareae and its biology and distribution is currently under investigation. T. koenigerum is smaller than T. clareae, with adult females being 0.7 mm long x 0.5 mm wide, oval and light brown, with males that are considerably smaller. Note that ongoing research in Asia may reveal the existence of other species of Tropilaelaps mites. More information is available in the advisory leaflet: Tropilaelaps: parasitic mites of honeybees
Current status
Currently neither Aethina tumida nor Tropilaelaps spp. have been found in the UK or the rest of Europe, but if introduced could potentially cause major damage in certain parts of the UK or Europe, if they became established. Both parasites are statutorily notifiable under EU legislation. The NBU Inspectorate carries out surveillance for these pests and beekeepers are strongly encouraged to monitor their hives for their presence, and diagnoses are carried out by the NBU laboratory staff.